从价值观的角度,说明“赠人玫瑰,手有余香”的道理。
数列{1n(n+1)}的前n项和为Sn,则S99等于
如果tanα=0.213,那么锐角α的度数大约为( )
选答语。
①What's your name? ____ A. I'm from China.
②Where are you from? ____ B. He's my grandpa.
③Who's that man?____ C. My name is Tutu.